Homogeneous formation of NO and N{sub 2}O from the oxidation of HCN and NH{sub 3} at 600--1000 C
Journal Article
·
· Combustion and Flame
The oxidation of HCN and NH{sub 3} with CO, CH{sub 4}, or H{sub 2} addition has been studied in the temperature range between 600 to 1,000 C. In most of the tests 10% oxygen was used. The experiments were carried out under well-defined conditions in a flow tube reactor made of quartz glass. The effects of NO addition and oxygen level have been tested. To study the importance of O/H radicals in the reaction mechanism and to confirm previous studies, iodine was added in some tests. A detailed chemical kinetic model was used to analyze the experimental data. In general, the model and experimental results are in good agreement. The results show that under the conditions tested CO significantly promotes NO and N{sub 2}O formation during HCN oxidation. During NH{sub 3} oxidation carbon-containing gaseous species such as CO and CH{sub 4} are important to promote homogeneous NO formation. In the system with CH{sub 4} addition, the conversion of HCN to N{sub 2}O is lower compared to the other systems. In the HCN/NO/CO/O{sub 2} system NO reduction starts at 700 C and the maximum reduction of approx. 40% is obtained at 800 C. For the NH{sub 3}/NO/CO/O{sub 2} system the reduction starts at 750 C and the maximum reduction is 50% at 800 C. Iodine addition shifts the oxidation of HCN, NO, and N{sub 2}O formation as well as NO reduction to higher temperatures. Under the conditions tested, it was found that iodine mainly enhances the recombination of the O-radicals. No effect on NO formation was found in the HCN/CH{sub 4}/O{sub 2} system when oxygen was increased from 6% to 10%, but when oxygen was increased from 2% to 6% NO formation decreased. The role of hydrocarbon radicals in the destruction of NO is likely to become important at low oxygen concentrations (2%) and at high temperatures (1,000 C).
- Research Organization:
- Vienna Univ. of Technology (AT)
- OSTI ID:
- 20019024
- Journal Information:
- Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 4 Vol. 120; ISSN CBFMAO; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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